Fuel injection pump



June 4, 1.957

Filed April 19, 1952 35 i FJ" P. G. BURMAN FUEL INJECTION PUMP 3Sheets-Sheet l PAUL e'. BUE MAN BY Ww/4% ATTPNEY 5 Sheets-Sheet 2 f. l l

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u "n un l v v INVENTOR. 'PAUL ,6. :BURP/IAN ATT/Vff June 4, 1957 P. G.BURMAN FUEL INJECTION PUMP June 4, 1957 P. G. BURMAN 2,794,397

FUEL INJECTION PUMP Filed April 19, 1952 5 Sheets-Sheet 3 TYPICAL 'RATEOf' :DISCHARGE .DIAG'EAMS FCE VARYING FUEL QUANTITY BY VA'EYING THEEFFECTIV `PLUNGE`E STROKE N Id 1L 6 IIJ )a LOAD 4 2- 72 LOAD s- 92 LOAD4- FULL LOAD :DISC HAEGE. PER STIZOK DEGREE m (n IDUEATION- CAM @EGEEESTYPICAL EAT: oF DISCHARGE Foz VATZYING FUEL QUANTITY BY f VAEYING THCAMOUNT oF FUEL 2 5 Jg 5 SPILLED THzuouT THE CONSTANT EFFECTIVE FLUNGEPSTROKE INVENTOR. PAUL G. BU'EMAN ATTOE/VEY raised States liatent FUELENECTEN PUB/lil' Z Claims. (Cl. 14373-2) This invention relates to fuelinjection apparatus and has particular reference to a new and improvedfuel injection pump which is capable of maintaining a practicallyconstant duration of injection regardless of fuel quantity delivered. t

An object of the invention is to provide a new and improved fuelinjection apparatus adapted to pump and distribute fuel to a pluralityof combustion chambers and which is relatively simple and inexpensive inconstruction and capable of maintaining a practically constant durationof injection regardless of fuel quantity delivered and which willprovide accurate distribution of the fuel to each of the combustionchambers.

Another object of the invention is to provide a new and improved fuelinjection apparatus having means forA controlling residual pressure.

Another object of the invention is toprovide a fuel pumping anddistributing apparatus in which the same delivery valve is utilized foreach of the outlets or discharge lines and which apparatus is providedwith a controlled bypass or spill means which is common to all of theoutlets.

Another object of the invention is to provide a new and improved bypassor spill control means for fuel injection apparatus and which isrelatively simple and inexpensive in construction and ecient inoperation.

Another object of the invention is to provide fuel injection apparatusof the type set forth with means for controlling the timing ofinjection.

Another object of the invention is to provide a new and improved fuelinjection apparatus of the type set forth in which the pumping mechanismhas a constant effective stroke and wherein means is provided forvarying the rate of delivery or injection during the stroke, whereby thepump will maintain a constant injection duration regardless of the fuelquantity delivered.

Other objects and advantages of the invention will be apparent from thefollowing description taken in connection with the accompanyingdrawings. It will be understood that changes may be made in the detailsof construction and arrangement of parts, as the preferred forms havebeen given by way of illustration only.

With fuel injection apparatus previously employed, the quantity of fuelinjected was controlled either by a metering valve or throttled inletarrangement which controlled the quantity of fuel reaching the pumpingbore, or where the spill or bypass type of fuel quantity control wasernployed, the arrangements used provided for spilling only at the endof the stroke and, therefore, with such apparatus the effective strokeof the pumping plunger was varied in all instances thereby makingimpossible the obtaining of a constant duration of injection regardlessof the fuel quantity, and it is therefore the principal object of thisinvention to provide new and improved means whereby it is possible toobtain constant duration of injection regardless of fuel quantityinjected.

Referring to the drawings:

Fig. 1 is a longitudinal sectional view of one form of fuel injectionapparatusV embodying the invention;

Fig. 2 is a sectional view of the hydraulic head of a fuel injectionpump but showing a slightly modified form of the invention; j A l Fig. 3is a sectional View similar to Fig. 2 with the addi,- tion of means forcontrolling the timing of injection;

Fig. 4 is a graph showing the typical rate of discharge diagrams forvarying fuel quantity by varying the elective plunger stroke; and

Fig. 5 is a graph showingthe typical rate of discharge diagrams forvarying the fuel quantity by means of the apparatus of the presentinvention.

Referring more particularly to thedrawings wherein similar referencecharacters designate corresponding parts throughout, the apparatus shownin Fig. ll comprises Vthe fuel injection pump 10 and governor 11 securedtogether to form a single relatively small compact unit which may bemounted on or removed from the engine as a single unit. If desired, thefuel supply pump which may be a conventional gear type supply pump orother desired form of such pump, may be secured as a part of such unitas shown in Patent 2,518,473 or,- if desired, the fuel supply pump maybe formed as 'a separate unit having the fuel supply line connected tothe fuel injection pump for supplying fuel thereto.

The fuel injection pump 10 lis adaptedlto be operated by the cam 12 on`camshaft 13, which camshaft is adapted to operate at half vengine speedor at engine speed, and the number of cam lobes included in cam 12 beingdependent upon the speed at which the camshaft is to be operated. j l

The camshaft 13 is mounted vfor rotation on ball bear-j ing 14 andbearing 15 adjacent its opposite ends and -the camshaft is provided withthe usual mounting ange for operatively connecting'the pump assembly tothe engine.

The fuel injection pump 10 and governor 11V are generally similar tothat shown and described Vin said Patent 2,518,473, 'except for thehydraulic head as hereinafter described and reference is hereby madeto-said Patent 2,518,473 for further description of the details of saidinjection pump and governor.

On the camshaft 13 is provided the helical gear 1,6 which is rotated bycamshaft 13 upon rotation of the carnshaft and said helical gear 16meshes with helical gear 17 on shaft 18 for effecting rotation of thepumping and distributing member of plunger 19 of the hydraulic head 20.

Hydraulic head 20 is provided with a bore 21 adapted to receive pumpingand distributing member or plunger 19 and said plunger 19 is adapted tobe reciprocated by cam 12 through tappet 22 to which the adjacent end ofsaid plunger 19 is secured by means of spring seat 23, which is retainedin engagement with the end of plunger 19 by spring 24 and rotation ofsaid pumping and distributing member or plunger 19 is effected through agear meshing with gear 16 driving a shaft on which is a gear adapted tomesh with and rotate gear 25, which is keyed to plunger 19 and adaptedto rotate the same upon rotation of said gear 25 in a manner similar tothat disclosed in Patent 2,518,473. Gear 17 drives shaft 18 for drivinga supply pump. y

Aligned with bore 21 in hydraulic head 2i) is provided delivery valve 26which communicates with said bore 21 through port 27 which is normallyclosed by piston or valve member 2S which in turn is normally retainedin closed position by valve spring 29.

The hydraulic head 20 is provided with the fuel inlet and spill port 3Bwhich is adapted to be connected to the fuel supply pump by a hydraulicline, not shown, and is adaptedto supply fuel through port 31 to bore 21and VEl fuel is adapted to be spilled or bypassed back to port 31through port 32 and annular peripheral groove 33 in plunger19.: 'A "{MIt will be seenfrom the foregoing-,thatathe pump'. is of constanteffective stroke." f'

' Fuel passing Vthrough delivery valve 26 passes through ducts 34 and 35to the annular peripheral groove 36 on plunger 19 which groove V36communicateswithdistributing groove 37 adapted to be aligned withthevdischarge passages 80 inl the hydraulic head communicating with eachof the youtlets 38a successively to thereby provide fuel to eachV of thecombusion chambers 1 in desired sequence. 1 l

While the injection duration k is, :nstant, the quantity of fuelinjected is controlled by the bypass or spill controlled valve 38 which,as shown in Fig. l, communicates with ducts 34 and 35 andV is variableby means of lever 39 and valve 38 is normally retained inclosed positionby spring 40, which allows automatic opening of the valve when thepressure in ducts 34 and 35 is sufficient to overcome the force ofspring 40 to allow the bypassing or in the fuel delivery line. Theadjusting lift of valve 3S through lever 39 also adjusts the quantity offuel bypassed or spilled and, therefore, controls the quantity of fueldelivered by the pump to each of the outlets 38a and thereby to thecombustion chambers.

The fuel bypassed or spilled by valve 38 passes through duct 41 to sump42 which also serves to collect'any fuel escaping past the plunger 19and said fuel is delivered through duct 43 from sump 42 to fuel inlet30.n

v In the forms shown in Figs. 1, 2 and 3, the bypass or spill 'controlvalve communicates with the fuel path between the delivery valve 26 andthe fuel distributor.

In the forms of the invention shown in Figs. 2 and 3, the bypass orspill controlvalve 38 is positioned above delivery valve 26 andcommunicates therewith by means of port 44 which allows the passage ofbypassed fuel into bypass chamber 45 from which itis returned by duct 46to fuel inlet 30. i

In the form of the plunger 19 is provided with passage 47 communicatingthrough port 48 with chamber 49, and the passage of fuel through port 48is controlled by sleeve 50 through eccentric 51 and control lever 52 tothereby control the timing the bypass control valve serves also toeffect constant` residual pressure in the yfuel delivery lines, thatisthe bypass valve allows the escape of pressure surges above desiredpressure and thereby allows control of the residual pressure in the fueldelivery lines. Y

This elimination of the retraction piston on the delivery valve has anadditional advantage in that the use of such piston limits thespeed ofoperation of the pump and by the elimination of such piston, the speedof the pumpcan be increased.

The main function of the bypass valve is to controlV the quantity offuel injected and allow the obtaining of constant injection durationregardless of quantity injected.V

In Figs. 4 and 5, this is graphically illustrated.

In Fig. 4, there is shown the variation in the rates of discharge forvarying fuel quantity by the prior art method of varying the effectiveplunger stroke, whereas in Fig. 5, there is shown typical rate ofdischarge diagrams for varying the fuel quantity by varying the amountof fuel spilled or bypassed throughout a constant effective plungerstroke. Y

- As will be seen from Fig. 4, with the prior art method there isobtained a fairly constant maximum rate of discharge for each of thedifferent loads and the duration' of injection becomes unduly short atlow loads which results in rough running of the engine with consequent Ythe bolts 61 or other suitable means.

invention shown Figi.,3, the Y The governor shaft 62 is keyed to thecamshaft 13 and adapted to rotate therewith.

The governor shaft 62 has a serrated portion 63 and a spider 64 isrigidly mounted upon the serrated portion 63 of the shaft 62. The spider64 supports the governor weights 65 which are pivotally mounted thereonand each` of the weights has a portion which contacts with the flange 66on sleeve 67 through the ball bearing 68. The sleeve 67 is mounted forlongitudinal movement upon the governor shaft 62 and at its opposite endfrom the flange A 66 lis provided with the flanges 69 and 70formingseats for the springs 71 and 72 respectively. s

A governor lever 73 is provided in the form of a yoke 74, the forks ofwhich extend around the governor shaft' 62 and each fork islpivotallymounted on the lever 75 which is pivotally mounted on the housing 60.Lever 73 pivots also on flange 70.

The governor lever 73 is provided with the cam 76 which is adapted toengage the plate 77 which is so adjusted that the cam 76 just touchesthis plate 77 at full connected to lever 73 at 73a and said link 81 isconnected to bell crank 83 which is carried by bracket 82 and isconnected to lever 39 for actuating the same.

'Ihe spring member 78 and adjustable surge screw 79 are provided forsteadying engine performance in case of any surging.

In operation the fuel pump by the pumping member 19 is the same on eachpumping stroke, that is, they device has constant effective stroke andtherate of delivery or injection is varied by controlling the amount offuel spilled or bypassed by valve 38 and, therefore, instead of spillingonly at the end of the stroke as with the prior art type of pumps, alittle of the fuel is spilled allrduring the injection which reduces thequantity injected by the y amount spilled and maintains a constantinjection duration throughout the entire load range.

'It will also lbe'noted that as the apparatus utilizes the same deliveryvalve and spill `control for injection through all of the outlets, thatthe injection through all of the youtlets will be precisely the same.

From the foregoing, it will be seen that I have simple,

eicient and economical means for r'obtaining all of theY objects andadvantages of the invention.

Y Iclaim: n

1. In a device of the character described, a housing having Ia bore, afuel supply port communicating with said bore for supplying fuelthereto, a pumping and Vdistributing member mounted for reciprocationand rotasaid fuel supply port, and adjustable valve means forcontrolling the passage of fuel through 'said bypass passage to saidfuel supply port and thereby controlling the lfuel 5 quantity deliveredto said outlets, said adjustable valve means being biased to closedposition by means exerting a variable force, and opened by pressure insaid fuel path whereby a practically constant duration of injection willbe maintained regardless of fuel quantity.

2. In Ia device of the character described, a housing having a bore, afuel supply port communicating with said bore for supplying fuelthereto, a pumping and distributing member mounted for reciprocation androtation in said bore and having a distributing slot in its periphery, aplurality of outlets communicating with said bore and adapted to receivefuel therefrom, a fuel path externally of said bore between the pumpingand distributing portions of said pumping and distributing member, adelivery valve in said fuel path, a bypass fuel passage communicatingwith said fuel path between said delivery valve and said distributingportion of said pumping and distributing member, 'said bypass Afuelpassage communicating with said fuel `supply port, and adjustable valvemeans for controlling the passage of fuel through said bypass passage tosaid fuel supply port and thereby controlling the fuel quantitydelivered to said outlets, said adjustable valve means being biased toclosed position by means exerting a variable force, and opened ibypressure in said fuel path whereby a practically constant duration ofinjection will be maintained regardless of fuel quantity.

References Cited in the le of this patent UNITED STATES PATENTS2,391,174 Lownsbery Dec. 18, 1945 2,470,583 Sedgwick May 17, 19492,518,473 Hogeman et al. Aug. l5, 1950 2,593,788 Parsons Apr. 22, 19522,657,631 Evans Nov. 3, 1953 2,667,840 High Feb. 2, 1954

